Solenoid valve

ABSTRACT

A substantially cylindrical annular space is formed by an outer circumferential surface of a cylindrical portion  4   a  and a substantially flat surface portion  4   b  of a substantially bottomed cylindrical sleeve  4,  an inner circumferential surface of a case member  9,  and a substantially flat surface portion  12   a  of a bracket plate  12,  a seal member  10  being provided in this annular space. Thus, the simplification of the construction, and the miniaturization and the reduction of the weight is realized while a sealing performance between the inside and outside of the main body is maintained.

TECHNICAL FIELD

[0001] This invention relates to a solenoid valve suitably used forcontrolling, etc., pressures of various kinds of fluids.

BACKGROUND ART

[0002] The conventional art solenoid valves of this kind include, forexample, a solenoid valve shown in FIG. 7. FIG. 7 is a schematicconstruction diagram in section of the conventional art solenoid valve.

[0003] The solenoid valve 200 includes a solenoid portion 200A, and avalve portion 200B.

[0004] Here, in the illustrated example, the valve portion 200Brepresents a spool valve type capable of controlling an inflow rate andan outflow rate of a fluid by varying a cross-sectional area of anopening of the valve in accordance with a stroke of a spool.

[0005] The solenoid portion 200A is generally provided with asubstantially cylindrical coil 203 adapted to generate a magnetic fieldwhen it is energized, a plunger 201 magnetically attracted to a centerpost 202 by the magnetic field generated in the coil 203, a rod 204connected to the plunger 201 so as to transmit a driving force of theplunger 201 to the valve portion 200B (spool specifically), and asubstantially bottomed cylindrical metal sleeve 205 provided so as tocover the outer surfaces of the plunger 201 and center post 202 for thepurpose of positioning (centering) the plunger 201 and center post 202.

[0006] Besides, the solenoid portion 200A is provided with an upperplate 206 forming a magnetic path, a molded section 207 in which thecoil 203 is integrally molded, and a metal case member 208 in whichthese members are held.

[0007] Also, the center post 202 is provided with a plate portion 202 aextended to radial direction in the vicinity of an opened end of thesleeve 205. At the end surface of the molded section 207 which is on theside of the plate portion 202 a, an inclined surface 207 a is provided.These plate portion 202 a, inclined surface 207 a and an innercircumferential surface 208 a of a case member 208 form a substantiallycross-sectionally triangular annular space.

[0008] This annular space is provided therein with a first O-ring 209,which closely contacts the plate portion 202 a, inclined surface 207 aand inner circumferential surface 208 a of the case member 208. Thus,the entry of the water (contaminants), which causes a poor insulation ofthe coil and the short-circuiting thereof, from the outside into aninner portion (bobbin) of a body of the solenoid valve 200 is prevented.

[0009] The cause of the poor insulation of this coil or the cause of theshort-circuiting thereof will now be described in detail. The portion ofthe center post 202 and that of a valve sleeve 202 c at which these twoparts are fixed to each other by case-caulking are liable to causedeformation, which results in a gap between these parts.

[0010] Moreover, at the metal upper plate 206 and an integrally moldedportion of a resin provided on the periphery thereof, a gap betweenthese portions occurs due to the expansion and contraction thereofascribed to the variation of the temperatures, because the metal andresin are comparatively different in a coefficient of linear expansion.

[0011] Therefore, the water flows from the outer side, and through thegap in the case caulked portions, and the water then flows from this gapin the case caulked portions and through the gap between an innercircumferential surface of the case and an outer circumferential surfaceof the molded portion, and/or from the gap between the innercircumference of the bobbin and the outer circumference of the sleeveand through the gap between the upper plate and resin portion to enterthe coil portion.

[0012] The center post 202 is provided in an outer circumference thereofwith an annular groove 202 b, in which a second O-ring 210 is alsoprovided. Since the second O-ring 210 closely contacts an innercircumference of the sleeve 205, a fluid (oil in a hydraulic pressurecontrol-dedicated) in the solenoid valve body is prevented from flowingto the outside.

[0013] The operation of the solenoid valve 200 will now be described.

[0014] The plunger 201 is formed so that when the plunger is in a normalcondition, i.e., when the coil 203 is not energized, the plunger 201 ispositioned in the direction in which the plunger is separated from thecenter post 202.

[0015] The plunger is generally formed so that the plunger is urged byan urging member, such as a spring and the like in the direction inwhich the plunger 201 is separated from the center post 202. In theillustrated example, a spring for urging the spool toward the solenoidportion 200A is provided, by which the plunger is separated from thecenter post 202 via the spool.

[0016] Also, when the coil 203 is energized, the coil 203 generates amagnetic field and a magnetic path is formed. The plunger 201 is thenmagnetically attracted to the center post 202.

[0017] Accordingly, a magnetic force can be controlled in accordancewith a level of the electric current supplied to the coil 203. When aquantity of movement of the plunger 201 is thereby controlled, aquantity of stroke of the spool can be controlled. This enables a flowrate of the fluid to be controlled, and pressures of various kinds offluids to be controlled such as a hydraulic pressure control.

[0018] However, in the above-described conventional art, the followingproblems occurred.

[0019] As described above, between the inside and the outside of themain body of the solenoid valve 200 in order to prevent the entry of thewater (contaminants), which causes a poor insulation of a coil and theshort-circuiting thereof, and the leakage of the fluid from the innerportion, it was necessary that two O-rings (first O-ring 209 and secondO-ring 210) be provided.

[0020] Incidentally among the members constituting the solenoid valvebody 200, the center post 202, sleeve 205 and case member 208, etc. aremade of a metal, while the molded portion 207, and bobbin around whichthe coil 203 is wound, etc. are made of a resin.

[0021] In particular, the first O-ring 209 prevents the water on theouter side of the valve from flowing from the caulked portion of thecase, and through the gap between the outer circumference of the moldcoil and the inner circumference of the case and/or a gap between theinner circumference of the bobbin and the outer circumference of thesleeve, and then through the gap between the upper plate and resin(mold) to enter the inner portion of the coil, and thereby prevents thepoor insulation and short-circuiting of the solenoid from occurring.

[0022] Also the second O-ring 210 is provided mainly for the purpose ofpreventing the leakage of the fluid from the inner portion.

[0023] This is because the leakage of the fluid (oil) in the directionof an arrow A in FIG. 7 causes the fluid to permeate and leak into theconnector portion, etc. and results in the malfunctions of gathering theoil in the connector, etc. if the second O-rings 210 is not provided.The leakage is caused by the gaps between the metal sleeve 205 andmolded portion 207, between the metal sleeve 205 and bobbin, and betweenthe metal upper plate 206 and bobbin because gaps readily occur betweenthe metal members and resin members as mentioned above.

[0024] Under the circumstances, the second O-ring 210 closely contactingthe metal center post 202 and sleeve 205 delivers a high sealingperformance.

[0025] Although a sufficient sealing performance is thus displayed owingto the use of the two O-rings, an increase in the number of parts andthe complication of the construction were invited.

[0026] It is necessary that an annular groove 202 b be provided in thecenter post 202 for fitting the second ring 210 therein, a magnetic fluxis hard to be formed between the portion which is provided with theannular groove 202 b and coil 203. This constituted a factor of causingthe solenoid valve 200 itself to be enlarged for securing a requiredmagnetic flux.

[0027] An object of the present invention is to provide a solenoid valvewhich has attained the simplification of the construction, theminiaturization and the reduction of the weight while the sealingperformance between inner and outer of the main body is maintained.

DISCLOSURE OF THE INVENTION

[0028] To achieve these objects, the present invention provides (1) asolenoid valve having:

[0029] a substantially cylindrical coil adapted to generate a magneticfield when it is energized,

[0030] a center post provided concentrically with the cylindrical coil,

[0031] a plunger adapted to be magnetically attracted to the center postby a magnetic field generated by the coil,

[0032] a substantially bottomed cylindrical metal sleeve provided so asto cover outer circumferential surfaces of the center post and plunger,

[0033] a metal plate provided in the vicinity of an opening end of thesleeve and having a substantially flat surface portion extending toradial direction, and

[0034] a metal case member containing these coil, center post, plunger,sleeve and plate,

[0035] the solenoid valve including a collar provided on the sleeve andextending toward an inner circumferential surface of the case member,

[0036] an annular space formed among one surface of the collar, an innercircumferential surface of the case member and a substantially flatsurface portion of the plate, and

[0037] a seal member provided in the space and adapted to seal each ofone surface of the collar, the inner circumferential surface of the casemember and the substantially flat surface portion of the plate.

[0038] According to this structure, the seal member seals each of theinner circumferential surface of the case member and the substantiallyflat surface portion of the plate, so that the entry of the water(contaminants), which causes a poor insulation of the coil and theshort-circuiting, from the outside can be prevented. Moreover, thesealing of the substantially flat surface portion of the plate and onesurface of the collar enables the leakage of the fluid from an inside tobe prevented. Therefore, one seal member enables the entry of water(contaminants), which causes a poor insulation of the coil and theshort-circuiting thereof, from the outside, and the leakage of the fluidfrom an inside to be prevented.

[0039] It is recommendable to:

[0040] form the annular space to a substantially cylindrical shape bythe outer circumferential surface formed by extending the collar in thedirection separating from the plate, and the substantially flat surfaceportion formed by bending the end portion of this outer circumferentialsurface toward the inner circumferential surface of the case member,

[0041] provide the seal member with:

[0042] a seal portion which forms a first seal surface with thesubstantially flat surface portion of the plate,

[0043] a contact portion contacting the substantially flat surfaceportion of the collar, and

[0044] a position restricting portion adapted to be brought into contactwith the outer circumferential surface portion of the collar andrestricting a radial inward movement,

[0045] render at least either one of the seal portion and contactportion flexible deformable toward the inner circumferential surface ofthe case member and form a second seal surface with the innercircumferential surface of the case member, and

[0046] form a third seal surface between at least either one of thecontact portion and position restricting portion and the collar.

[0047] According to this structure, a radial inward movement isrestricted with the position restricting portion, so that the sealingperformance of the second seal surface even with respect to a variationof an axial size is maintained. Moreover, when a load is imparted in theaxial direction, a sufficient sealing performance is delivered by eitherone of the seal portion flexibly deformable toward the innercircumferential surface of the case member and the contact portion.

[0048] It is recommended that the annular space be formed to asubstantially triangular cross-sectional shape by inclining the collarso that the collar becomes distant from the plate from a position inwhich the collar contacts the plate toward the inner circumferentialsurface of the case member, and that:

[0049] the seal member be made of an O-ring adapted to seal each of theinclined surface of the collar, the inner circumferential surface of thecase member and the substantially flat surface portion of the plate.

[0050] Owing to this structure, one seal member, i.e. even such a simpleseal member as the O-ring can prevent the entry of the water(contaminants), which causes a poor insulation of the coil and theshort-circuiting, from the outside, and the leakage of a fluid frominside.

[0051] It is recommended that the collar be formed out of an elasticallydeformable elastic material, and that:

[0052] the collar be disposed so as to press the seal member by anelastic resilience of the collar.

[0053] This arrangement enables a variation of the sizes of the sealmember and seal space to be absorbed.

[0054] The solenoid valve (2) according to the present invention isprovided with:

[0055] a seal member adapted to seal at once a clearance between a valveportion and an inner portion of a coil, and a clearance between an outerportion and the inner portion of the coil,

[0056] at least a part of an outer wall forming a seal space in whichthe seal member is disposed being formed by an elastically deformableplate type member,

[0057] the plate type member being disposed so as to press the sealmember by an elastic resilience.

[0058] Therefore, a variation of the sizes of the seal member and sealspace can be absorbed.

[0059] The feature resides in that a restricting portion for restrictinga deformation region of the plate type member is provided so that thedeformation of the plate type member is held in an elastic range.

[0060] This can prevent the plate type member from being plasticallydeformed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0061]FIG. 1 is a schematic construction diagram in section of a firstembodiment of the solenoid valve according to the present invention;

[0062]FIG. 2 is a schematic construction diagram in section showing aseal member in an installed state in the first embodiment of the presentinvention;

[0063]FIG. 3 is a partially cutout view in section showing a modifiedexample of the seal member;

[0064]FIG. 4 is a schematic construction diagram in section of a secondembodiment of the solenoid valve according to the present invention.

[0065]FIG. 5 is a schematic construction diagram in section of a sealmember in an installed state in a third embodiment of the presentinvention;

[0066]FIG. 6 is a schematic construction diagram in section showing aseal member in an installed state in a fourth embodiment of the presentinvention; and

[0067]FIG. 7 is a schematic construction diagram in section of aconventional art solenoid valve.

BEST MODE FOR CARRYING THE INVENTION

[0068] Preferred of embodiment of the present invention will now beillustratively described in detail referring to the drawings. The size,material, shape and relative disposition and the like of the constituentparts described in the embodiment do not intend to limit the scope ofthe invention only thereto unless a specific description is given inparticular.

[0069] (First Embodiment)

[0070] A first embodiment of the solenoid valve according to the presentinvention will now be described referring to FIG. 1 and FIG. 2.

[0071]FIG. 1 is a schematic construction diagram in section of the firstembodiment of the solenoid valve according to the present invention, andFIG. 2 is a schematic construction diagram in section of a seal memberin an installed state in the first mode of embodiment of the presentinvention.

[0072] A solenoid valve 100 includes a solenoid portion 100A and a valveportion 100B.

[0073] Here, the valve portion 100B in the illustrated embodiment ismade of a spool valve. That is, the valve portion 100B is formed with aspool 15 provided in the interior of a valve sleeve 16 so that the spool15 can be reciprocated therein, the area of an opening of the valveformed in the valve sleeve 16 varies in accordance with a stroke of thespool 15. Therefore, the controlling of a quantity of stroke of thespool 15 by the solenoid enables an inflow rate and an outflow rate of afluid to be controlled.

[0074] The solenoid portion 100A is generally provided with asubstantially cylindrical coil 3 adapted to generate a magnetic field byenergizing, a plunger 1 adapted to be magnetically attracted to a centerpost 2 when a magnetic circuit is formed by a magnetic field generatedowing to energize the coil 3, a substantially bottomed cylindrical metalsleeve 4 constituting a bearing for the plunger 1, and a rod 7 connectedto the plunger 1 for transmitting a driving force of the plunger 1 tothe spool 15.

[0075] The solenoid portion 100A is also provided with a bracket plate12 which has a substantially flat section 12 a extended to radialdirection so as to form a magnetic path, and which has a bracket 12 bfor fixing a solenoid valve body in a predetermined position, and a casemember 9 holding therein various kinds of constituent members includinga coil 3, a center post 2, a plunger 1, sleeve 4 and bracket plate 12.

[0076] The solenoid portion 100A is further provided with a bobbin 6around which the coil 3 is wound, a shim 8 for having the plunger 1separate from the center post 2 easily, an upper plate 11 adapted toform a magnetic path, a bearing 13 for a rod 7, a spring 14 adapted tourge an E-type ring 18 fixed to the spool 15, and thereby urge theplunger 1 via the spool 15 and rod 7 in the direction in which theplunger 1 separates from the center post 2, and a connector 17 having aterminal 17 a for energizing the coil 3.

[0077] The coil 3 and bobbin 6 are assembled by molding, and form amolded coil sub-assembly 5.

[0078] This embodiment is also provided with a seal member 10 whichprevents the leakage of a fluid from an inner section of the valveportion 100B toward the coil 3, and the entry of the water(contaminants), which causes a poor insulation of the coil and theshort-circuiting thereof, from the outside; and which constitutes a mainmember of the characteristics of this embodiment.

[0079] The operation of the solenoid valve 100 will now be described.

[0080] The plunger 1 is formed so that, when the plunger 1 is in anormal condition, i.e., in the condition in which the coil 3 is notenergized, the plunger 1 is positioned in the direction in which theplunger 1 is separated from the center post 2. Namely, in thisembodiment, the plunger 1 is separated from the center post 2 when thespool 15 is urged toward the solenoid portion 100A via the E-type ring18 as mentioned above.

[0081] Also, when the coil 3 is energized, a magnetic path (a magneticpath formed by the case member 9, upper plate 11, plunger 1, center post2, and bracket plate 12) is formed, and the plunger 1 is magneticallyattracted to the center post 2.

[0082] Therefore, a magnetic force can be controlled in accordance withthe magnitude of the electric current supplied to the coil 3. When thequantity of movement of the plunger 1 is thereby controlled, thequantity of stroke of the spool 15 can be controlled. This enables aflow rate of a fluid to be controlled, and the controlling of variouskinds of fluid pressures and etc. including the controlling of ahydraulic pressure to be done.

[0083] The structure in this embodiment is not similar to a generalstructure of the solenoid in which both end portions of a plunger aresupported on a bearing respectively, but is formed so that the plunger 1is supported on bearings by the sleeve 4. Accordingly, the number ofmembers (S members including plunger 1, rod 7, center post 2, sleeve 4and rod bearings 13) having relation with the centering of the valve iscomparatively small, so that a load on the managing of the sizes is low.Furthermore, this solenoid valve is advantageous in that an axialdirection can be miniaturized as compared with a case where a bearingstructure is needed at both end portions respectively of the plunger.

[0084] The seal member 10 will now be described more in detail referringto, especially, FIG. 2.

[0085] This embodiment of the present invention is formed such that theportion of a collar which is at an end portion of an opening of thesubstantially bottomed cylindrical sleeve 4 is extended to a position inthe vicinity of an inner circumferential surface of the case member 9.In this mode of embodiment, a cylindrical portion 4 a is formed by bendfrom a position contacting the substantially flat surface portion 12 aand extension in the direction separating from the substantially flatportion and a substantially flat surface portion 4 b is formed byfurther bend toward an inner circumferential surface of the case member9.

[0086] A substantially cylindrical annular space is thus formed by anouter circumferential surface of the cylindrical portion 4 a,substantially flat surface section 4 b, an inner circumferential surfaceof the case member 9, and a substantially flat surface portion 12 a ofthe bracket plate 12.

[0087] The seal member 10 is provided in this annular space.

[0088] The seal member 10 is generally provided with a positionrestricting portion 10 a adapted to contact the outer circumferentialsurface of the cylindrical portion 4 a of the collar of the sleeve 4 andrestricted with respect to a radial inward movement, a contact portion10 b adapted to contact the substantially flat section 4 b of the collarof the sleeve 4, and a seal portion 10 c adapted to seal thesubstantially flat surface portion 12 a of the bracket plate 12.

[0089] In this mode of embodiment, a first seal surface is formedbetween the seal portion 10 c and the substantially flat surface portion12 a of the bracket plate 12, and a second seal surface is formedbetween the seal portion 10 c and the inner circumferential surface ofthe case member 9 and between the contact section 10 b and the innercircumferential surface of the case member 9. A third seal surface isformed between the contact portion 10 b and the substantially flatsurface portion 4 b of the collar of the sleeve 4 and between theposition restricting portion 10 a and an outer circumferential surfaceof the cylindrical portion 4 a of the collar of the sleeve 4.

[0090] In this mode of embodiment, the contact portion 10 b and sealportion 10 c are formed so that these portions can be flexibly deformedtoward the inner circumferential surface of the case member 9.

[0091] Since the contact portion 10 b and seal portion 10 c are thusformed as flexible lips, satisfactory sealing becomes possible even withrespect to the existence of a variation of the sizes of the annularspace.

[0092] In particular, in this embodiment, the lip-like contact portion10 b and seal portion 10 c are provided so that the cross-sectionbecomes a substantially U-shape in the vicinity of the-innercircumferential surface of the case member 9. Therefore, the flexibilityin the axial direction is sufficiently obtained so that these portionscan display a sufficient sealing performance even with respect to theexistence of a variation of the axial sizes. When a load is imparted inthe axial direction (in the direction of an arrow P in FIG. 2), each ofthe lip is bent (as shown by broken lines in FIG. 2) in the axiallyinward direction (in the direction of an arrow Q in FIG. 2), so that thesealing performance with respect to the inner circumferential surface ofthe case member 9 can be secured or backed up.

[0093] Namely, in the solenoid valve of the type in which the axial sizeis larger than the diametrical size with each member fixed by axiallycaulking the end portion of the case member 9 just as in thisembodiment, a variation of the sizes in the axial direction is liable tobecome larger (by around 3 to 4 times in dimensional tolerance) ascompared with that of the sizes in the diametrical direction, and a loadis imparted to the solenoid valve in the axial direction during thecaulking operation. However, when the above-mentioned seal member 10 isused, a sufficient sealing performance of the solenoid valve can besecured.

[0094] In this embodiment, an annular projection 10 d is provided in thevicinity of a root of the lip of the contact portion 10 b, and anannular projection 10 e in the vicinity of the lip of the seal portion10 c.

[0095] Accordingly, shown in the drawing, a sealing operation may beaided by bringing the annular projection 10 d into close contact withthe substantially flat portion 4 b of the collar, and bringing theannular projection 10 e into close contact with the substantially flatsurface 12 a of the bracket plate 12.

[0096] Owing to the above-described structure, the seal portion 10 c ofthe seal member 10 seals the substantially flat portion 12 a of themetal bracket plate 12, and also the inner circumferential surface ofthe metal case member 9. This enables the entry of the water(contaminants), which causes a poor insulation of the coil and theshort-circuiting thereof, from the outside to be prevented.

[0097] Also, since the position restricting portion 10 a of the sealmember 10 seals the outer circumferential surface of the cylindricalportion 4 a of the collar of the metal sleeve 4, the leakage of a fluidfrom an inner portion of the solenoid valve can be prevented.Furthermore, since the contact portion 10 b seals the substantially flatsurface portion 4 b of the collar of the metal sleeve 4, the leakage ofthe fluid can be doubly prevented.

[0098] Thus, it becomes possible by one seal member 10 to simultaneouslyprevent the entry of the water (contaminants), which causes a poorinsulation of the coil and short-circuiting, from the outside, and theleakage of a fluid from an inner portion of the solenoid valve.

[0099] Therefore, the reduction of the number of parts and thesimplification of the construction of the solenoid valve become possibleas the excellent sealing performance is maintained. Unlike aconventional art solenoid valve of this kind, it is unnecessary that anannular groove for fitting an O-ring be provided in the center post.Therefore, even when the center post is made smaller, a magnetic pathcan be secured satisfactorily, so that the dimensions and weight of thesolenoid valve can be reduced.

[0100] Incidentally, the above-described embodiment shows a case whereall of the contact portion 10 b and seal portion 10 c is formed so as tobe flexibly deformable, and so as to provide a second seal surface withthe inner circumferential surface of the case member 9. However, eitherone only of them may be formed so as to be flexibly deformable, and soas to provide a second seal surface is formed with the innercircumferential surface of the case member 9.

[0101] Furthermore although the above-described embodiment shows a casewhere all of the position restricting portion 10 a and contact portion10 b are formed so that they constitute the third seal surfaces with thecollar of the sleeve 4, it is also possible that the third seal surfaceis formed with only one of them, and that the other is simply broughtinto contact.

[0102] The construction of the seal member is not limited to that shownin FIG. 2 but the construction shown in, for example, FIG. 3 may also beemployed.

[0103] A seal member 30 shown in FIG. 3 is generally provided with aposition restricting portion 30 a adapted to be brought into contactwith an outer circumferential surface of a cylindrical portion 4 a of acollar of a sleeve 4 and thereby restricted with respect to an inwardmovement, a contact portion 30 d adapted to contact a substantially flatsurface portion 4 b of a collar of a sleeve 4, a first seal portion 30 eadapted to seal a substantially flat surface 12 a of a bracket plate 12,and a second seal portion 30 b and a third seal portion 30 c adapted toseal an inner circumferential surface of a case member 9. Namely, thecontact portion 10 b of the seal member 10 shown in FIG. 2 is dividedinto the second seal portion 30 b and the contact portion 30 d in theseal member 30 shown in FIG. 3. Also, the seal portion 10 c of the sealmember 10 shown in FIG. 2 is divided into the first seal portion 30 eand the third seal portion 30 c in the seal member 30 shown in FIG. 3.

[0104] Also, the first seal portion 30 e forms a first seal surface, thesecond seal portion 30 b and third seal portion 30 c form a second sealsurface, and the position restricting portion 30 a and contact portion30 d form a third seal surface.

[0105] Also, the second seal portion 30 b, third seal portion 30 c,contact portion 30 d and first seal portion 30 e are made flexiblydeformable.

[0106] Accordingly, a stable sealing performance can be maintained evenwith respect to even a variation of the sizes thereof in the same manneras the seal member 10 shown in FIG. 2.

[0107] A preferred applied example of the solenoid valve 100 in thisembodiment will now be described.

[0108] In an engine for an automobile and etc. intake and exhaust valvesof the engine are opened and closed in accordance with a rotation of acamshaft. When the timing of the valve is controlled suitably inaccordance with the operating condition (high speed, low speed), thefuel efficiency can be improved, and a high exhaust gas purification canbe obtained.

[0109] This control for valve timing can be done by changing a phase byshifting the camshaft in the rotational direction. The techniques forcarrying out it by a solenoid valve are known as known techniques.

[0110] Here, in order to shift the camshaft in the rotational direction,a hydraulic pressure control by the solenoid valve is necessarilycarried out. The solenoid valve is generally provided on a path of anengine oil flow passage in relation to spaces for installation and etc.and uses the engine oil.

[0111] Conventionally, control were separately carried out according tothe two kinds of condition of a high-speed condition and a low-speedcondition by using a solenoid valve adapted to carry out an ON-OFFcontrol. However, in recent years, a solenoid valve capable of carryingout a linear control has come to be used so as to carry out a morehighly accurate control.

[0112] Therefore, the solenoid valve according to the above-describedembodiment of the present invention becomes possible to be used suitablyas such a valve timing control (VTC) linear control solenoid valve.

[0113] (Second Embodiment)

[0114]FIG. 4 shows a second embodiment. In the first embodiment, a casewhere an annular space is formed in a substantially cylindrical shapewith a substantially rectangular cross section and it receives a sealmember of a special shape, which can deal with variations of the axialdimensions and shape, was described. In the second embodiment, a casewhere an annular space is formed to a substantially triangular crosssectional shape with a three-surface sealing in which each surface issealed by O-rings will be described.

[0115] The other construction and function are identical with those ofthe first embodiment, so that a description of the same parts will beomitted.

[0116]FIG. 4 is a schematic construction diagram in section of thesolenoid valve according to a second embodiment of the presentinvention. A seal portion shown by an arrow P in the drawing is shown onan enlarged scale (P) in the drawing.

[0117] In the embodiment of the present invention, a collar at an endportion of an opening of a substantially bottomed cylindrical sleeve 4is formed so as to extend to the vicinity of an inner circumferentialsurface of a case member 9. In this embodiment, an inclined surface 4 cis provided which is formed by bending the collar at the portion whichcontacts a substantially flat surface portion 12 a of a bracket plate12, and which extends gradually away from the substantially flat surfaceportion 12 a with extending toward an inner circumferential surface ofthe case member 9.

[0118] Thus, an annular space of a substantially triangularcross-sectional shape is formed by these inclined surface 4 c of thesleeve 4, inner circumferential surface of the case member 9 andsubstantially flat surface portion 12 a of the bracket plate 12.

[0119] Also, in this annular space, a seal member 20 is provided.

[0120] The seal member 20 in this embodiment is an O-ring serving as athree-surface seal contacting closely and sealing all of the inclinedsurface 4 c of the sleeve 4, the inner circumferential surface of thecase member 9 and the substantially flat surface portion 12 a of thebracket plate 12.

[0121] Owing to such a structure, the seal member 20 closely contactsthe substantially flat surface portion 12 a of the metal bracket plate12 and also the inner circumferential surface of the metal case member9, and the entry of the water (contaminants), which causes a poorinsulation of a coil and the short-circuiting, from the outside becomespossible to be prevented.

[0122] Since the seal member 20 closely contacts the inclined surface 4c of the collar of the metal sleeve 4, the leakage of a fluid from theinterior of a solenoid valve can be prevented.

[0123] Thus, the prevention of the entry of the water (contaminants),which causes a poor insulation of the coil and the short-circuitingthereof, from the outside, and the leakage of the fluid from an innerportion become able to be carried out at once by one seal member 20, andthe same effect as in the first mode of embodiment can be obtained.

[0124] In this embodiment, an O-ring that whose construction is simpleis used as a seal member, so that the construction of a sealmember-installing portion is also naturally simple. This enables theconstruction of the solenoid valve to be more simplified.

[0125] (Third Embodiment)

[0126] The solenoid valve according to the present invention of a thirdembodiment will now be described referring to FIG. 5. Incidentally, inthis embodiment the construction except the construction of a sealmember and a collar of a sleeve 4 is identical with the firstembodiment. Therefore, they only will be described in detail, and adescription of the other construction will be omitted.

[0127]FIG. 5 is a schematic construction diagram in section of the sealmember in an installed state according to the third embodiment of thepresent invention.

[0128] In this embodiment, a substantially flat surface portion 4′b of acollar of a sleeve 4 is made elastically deformable. Namely, asubstantially flat surface portion 4′b is formed as a flexible leafspring in which a bent portion 4′d between a cylindrical portion 4′a andsubstantially flat surface portion 4′b works as a base point where apower is received.

[0129] When a seal member 40 is installed in such a structure, thesubstantially flat surface 4′b is pressed and bent by contact portion 41provided on the seal member 40. As a result, the contact portion 41provided on the seal member 40 is pressed by an elastic resilience ofthe substantially flat surface portion 4′b.

[0130] Therefore, owing to a synergistic effect of the elasticresilience of the seal member 40 and that of the substantially flatsurface portion 4′b, sufficient sealing performance is delivered.

[0131] Here, a seal space (annular space) in which this seal member isinstalled is formed by the collar of the sleeve 4, an innercircumferential surface of a case member 9 and a substantially flatsurface portion 12 a of the bracket plate 12. Due to a variation of thesizes of these members, the dimensions of the seal space vary.

[0132] A variation also occurs in the sizes of the seal member 40.

[0133] However, when a part (the substantially flat surface portion 4′bwhich also constitutes a part of the collar) of an outer wall formingthe seal space is made of an elastically deformable elastic material asin this embodiment, the above-mentioned variation of the dimensions canbe absorbed.

[0134] Therefore, even when the volume of the seal member is large withrespect to seal space, an increasing crushing load deforms thesubstantially flat surface portion 4′b, and enlarges the seal space, sothat a stable sealing performance can be obtained without causing apacking rate of the seal member to exceed 100%.

[0135] Since the deformation of substantially flat surface portion 4′benlarges the seal space, an installing load of the seal member can bereduced without causing the packing rate to increase to an excessivelyhigh level, and an installing efficiency is improved.

[0136] Thus, with respect to a variation of the sizes of the seal spaceand a variation of the sizes of the seal member, an insufficienttightening margin (crushing margin) of the seal member or an excess ofthe packing rate of the seal member over 100% can be prevented.

[0137] In this embodiment, an end surface 51 of a molded portion of amolded coil sub-assembly 5 is given a function as a restricting portionfor restricting a deformation region of the substantially flat surfaceportion 4′b.

[0138] This enables the deformation region of the substantially flatportion 4′b to be restricted within an elastic range and the plasticdeformation of the substantially flat portion 4′b to be prevented.

[0139] Incidentally, as a material (material for the sleeve 4) for thesubstantially flat surface portion 4′b, for example, stainless steel canbe suitably used.

[0140] Also, when a thin plate material is bent in manufacture of thesubstantially flat surface portion 4′b, a bent rounded portion (bentportion 4′d) is liable to become thinner, so that this portion issuitable as a base portion of flexure of a leaf spring. Therefore, whenthe thickness of this bent portion 4′d is regulated, a flexure load onthe leaf spring can be regulated

[0141] (Fourth Mode of Embodiment)

[0142] The solenoid valve according to a fourth embodiment of thepresent invention will now be described referring to FIG. 6. In thisembodiment, the construction except a collar of a sleeve 4 is identicalwith the second embodiment. Therefore, they only will be described indetail, and a description of the other construction will be omitted.

[0143]FIG. 6 is a schematic construction diagram in section showing aseal member in an installed state of the fourth embodiment of thepresent invention.

[0144] In this embodiment, an end portion (portion having an inclinedsurface 4′c) of the collar of the sleeve 4 is made elasticallydeformable in the same manner as in the above-described thirdembodiment. Namely, a bent portion 4′e, which is a root portion of theinclined surface 4′c, includes a base point where a power is received,and the end portion of the collar is formed as a flexible leaf spring.

[0145] When the seal member 20 (O-ring) is installed in such anarrangement, the end portion of the collar is pressed and bent. As aresult, the seal member 20 is pressed by an elastic resilience of theend portion of the collar.

[0146] Therefore, the effect identical with that in the above-describedthird embodiment becomes possible to be obtained.

[0147] In the fourth embodiment, an end surface 61 of a bobbin 6 is madeto function as a restricting portion for holding a deformation region ofthe end portion of the collar within an elastic range.

INDUSTRIAL APPLICABILITY

[0148] As described above, the present invention is capable ofpreventing the entry of the water (contaminants), which causes a poorinsulation of the coil and the short-circuiting, from the outside andthe leakage of a fluid from the inside, by one seal member, simplifyingthe construction of the solenoid valve and reducing the dimensions andweight while maintaining the sealing performance between the inner andouter portions of the main body.

[0149] Since the annular space portion is formed to a substantiallycylindrical shape in which a seal member, which is provided with a sealportion, contact portion and a position restricting portion ininstalled, a sufficient sealing performance can be delivered even withrespect to variation in the dimensions of the annular space especiallyin the axial direction.

[0150] When the annular space is formed to a substantially triangularcross-sectional shape in which an O-ring is installed, the constructioncan be more simplified.

[0151] When at least a part of the outer wall forming the seal space ismade of an elastically deformable plate type member, by an elasticresilience of which the seal member is pressed, a variation of thedimensions of the seal member and seal space can be absorbed, and a morestable sealing performance is delivered.

1. A solenoid valve provided with: a substantially cylindrical coil adapted to generate a magnetic field when it is energized, a center post provided concentrically with the cylindrical coil, a plunger adapted to be magnetically attracted to the center post by a magnetic field generated by the coil, a substantially bottomed cylindrical metal sleeve provided so as to cover outer circumferential surface of the center post and plunger, a metal plate provided in the vicinity of an opening end of the sleeve and having a substantially flat surface portion extending to radial direction, and a metal case member containing these coil, center post, plunger, sleeve and plate, characterized in that: the solenoid valve includes a collar provided on the sleeve and extending toward an inner circumferential surface of the case member, an annular space formed among one surface of the collar, an inner circumferential surface of the case member and a substantially flat surface portion of the plate, and a seal member provided in the space and adapted to seal each of one surface of the collar, the inner circumferential surface of the case member and the substantially flat surface portion of the plate.
 2. A solenoid valve according to claim 1, wherein the annular space is formed to a substantially cylindrical shape by the outer circumferential surface formed by extending the collar in the direction separating from the plate, and the substantially flat surface portion formed by bending the end portion of this outer circumferential surface toward the inner circumferential surface of the case member, the seal member being provided with: a seal portion which forms a first seal surface with the substantially flat surface portion of the plate, a contact portion contacting the substantially flat surface portion of the collar, and a position restricting portion adapted to be brought into contact with the outer circumferential surface portion of the collar and restricting a radial inward movement, at least either one of the seal portion and contact portion being rendered flexibly deformable toward the inner circumferential surface of the case member, and forming a second seal surface with the inner circumferential surface of the case member, a third seal surface being formed between at least either one of the contact portion and position restricting portion and the collar.
 3. A solenoid valve according to claim 1, wherein the annular space is formed to a substantially triangular cross-sectional shape by inclining the collar so that the collar becomes distant from the plate from a position in which the collar contacts the plate toward the inner circumferential surface of the case member, the seal member being made of an O-ring adapted to seal each of the inclined surface of the collar, the inner circumferential surface of the case member and the substantially flat surface portion of the plate.
 4. A solenoid valve according to claim 1, 2 or 3, wherein at least a part of the collar is made of an elastic material capable of being elastically deformed, the collar being disposed so that the seal member is pressed by an elastic resilience of the collar.
 5. A solenoid valve provided with a seal member adapted to seal at once a clearance between a valve portion and an inner portion of a coil, and a clearance between an outer portion and the inner portion of the coil, characterized in that: at least a part of an outer wall forms a seal space in which the seal member is disposed being formed by an elastically deformable plate type member, the plate type member being disposed so as to press the seal member by an elastic resilience.
 6. A solenoid valve according to claim 5, wherein a restricting portion for restricting a deformation region of the plate type member is provided so that the deformation of the plate type member is held in an elastic range. 